How to Delete Color Stops of Color Ramp using Python
You can remove them but not the last one.

If cr_node is the color ramp node, stops are stored in cr_node.color_ramp.elements.

You can remove the element n by:

cr_node.color_ramp.elements.remove( cr_node.color_ramp.elements[n] )


But if you attempt to remove the last one, you will have this error message:

RuntimeError: Error: Element not found in element collection or **last element**


So you need to keep it and change its values:

cr_node.color_ramp.elements[0].color = your color
cr_node.color_ramp.elements[0].position = your position